Core detection device of coring instrument

ABSTRACT

A core detection device of a coring instrument includes a base body and a core switch mechanism provided on the base body. The base body is provided with a core channel communicated with a core barrel. The core switch mechanism includes a detection portion, a connecting rod assembly and a travel switch which are sequentially arranged and connected along a length direction of the coring instrument. The detection portion is rotatably installed on the base body and one end thereof is extended into the core channel, so that a core passing through the core channel pushes the detection portion to rotate. The connecting rod assembly can be pulled by the rotating detection portion to trigger the travel switch to operate. The core switch mechanism adopts a slider-connecting rod structure, and the kinematic pairs are mainly a sliding pair and a rotating pair.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority to Chinese patent application No.202010171021.5 filed on Mar. 12, 2020, the entirety of which is herebyincorporated by reference.

TECHNICAL FIELD

The disclosure relates to the field of petroleum exploration anddevelopment, in particular to a core detection device of a coringinstrument.

BACKGROUND

In the process of coring with cables, the accurate detection of thesuccess of coring in real time and measurement of the quality of theretrieved core underground are very important for improving coringefficiency and coring quality. In addition, it is also crucial forgeological analysis to accurately determine the horizon of the requiredcore. At present, the number of cores retrieved by a coring instrumentat one time can be as high as 80, which is difficult to return to thecoring position, especially in a fragile fractured formation. Therefore,a core detection device is provided in the coring instrument, which canmonitor whether the coring is successful in real time, measure thelength of core and judge whether its quality meets the standard. If thepurpose of coring is not achieved, the depth can be immediatelyrelocated and a re-coring is performed. The core detection deviceincludes a core switch provided at an entrance of a core storage barrel,but the existing core switch is complex in structure and is prone to bestuck in the actual on-site application process, which makes itincapable of accurately detecting the core, and it occupies a largespace in the radial direction of the instrument.

SUMMARY

An embodiment of the disclosure provides a core detection device of acoring instrument, including a base body and a core switch mechanismprovided on the base body. The base body is provided with a core channelin communication with a core barrel. The core switch mechanism includesa detection portion, a connecting rod assembly and a travel switch whichare sequentially arranged and connected along a length direction of thecoring instrument. The detection portion is rotatably installed on thebase body and one end thereof is extended into the core channel, so thata core passing through the core channel pushes the detection portion torotate. The connecting rod assembly can be pulled by the rotatingdetection portion to trigger the travel switch to operate.

Other features and advantages of the disclosure will be set forth in thedescription which follows, and in part will be obvious from thedescription, or may be learned by implementation of the disclosure. Theobjects and other advantages of the disclosure can be realized andobtained by structures particularly indicated in the description and theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are used to provide a further understanding oftechnical solutions of the disclosure, and constitute a part of thespecification, which are used together with the embodiments of thepresent application to explain the technical solutions of thedisclosure, and do not constitute a restriction on the technicalsolutions of the disclosure.

FIG. 1 is a schematic diagram of a coring instrument according to anembodiment of the disclosure;

FIG. 2 is a sectional view of the core detection device in FIG. 1 ;

FIG. 3 is a first schematic diagram of the core detection device in FIG.1 ;

FIG. 4 is a second schematic diagram of the core detection device inFIG. 1 ;

FIG. 5 is a schematic diagram of the main body in FIG. 1 ; and

FIG. 6 is a schematic diagram of the slider in FIG. 1 .

Reference signs: 100—protective outer barrel, 200—core barrel,300—spacer barrel, 301—compression spring, 302—spacer, 400—base body,401—core channel, 402—main body, 403—partition plate, 404—installationcavity, 405—sliding cavity, 406—communication channel, 407—spacerchannel, 408—connecting post, 409—guide rib, 410—chute, 411—gap,500—core switch mechanism, 501—detection portion, 502—connecting rodassembly, 503—travel switch, 504—elastic member, 505—pull rod,506—connector, 507—first housing, 508—guide base, 509—insulating sleeve,510—copper screw, 511—pressing sleeve, 512—first sealing loop, 513—firstretaining ring, 514—first end cap, 515—first shell, 516—lower joint,517—first rotating shaft, 518—fourth rotating shaft, 519—fifth rotatingshaft, 520—first sealing ring, 521—second sealing ring, 522—first guidepost, 523—connecting rod, 600—spacer insertion mechanism, 601—slider,602—rotating arm, 603—cylinder body, 604—second housing, 605—secondguide post, 606—connecting base, 607—second end cap, 608—second shell,609—plug, 610—adjusting screw, 611—second sealing loop, 612—secondretaining ring, 613—third sealing ring, 614—fourth sealing ring,615—bracket, 616—receiving notch, 617—third rotating shaft, 618—secondelongated hole, 619—first elongated hole, 620—second rotating shaft,621—sixth rotating shaft, 622—guide groove, 623—slider body, 624—arcsurface, 700—displacement detector, 801—core pushing piston rod,802—core pushing head, 900—coring bit, 1000—controller.

DETAILED DESCRIPTION

In order to make the objects, technical solutions and advantages of thedisclosure clearer, embodiments of the disclosure will be described indetail with reference to the accompanying drawings. It should be notedthat the embodiments in the present application and the features in theembodiments can be arbitrarily combined with each other if there is noconflict.

Referring to FIGS. 1 to 6 , a core detection device of a coringinstrument according to the disclosure is shown. As shown in FIG. 1 andFIG. 2 , the core detection device is placed in a protective outerbarrel 100, which can protect various components in the core detectiondevice from impact. The core detection device includes a base body 400and a core switch mechanism 500 provided on the base body, and the basebody 400 is provided with a core channel 401 in communication with acore barrel 200, so that a core retrieved by drilling needs to be pushedinto the core barrel 200 after passing through the core channel 401. Thecore switch mechanism 500 includes a detection portion 501, a connectingrod assembly 502 and a travel switch 503 which arc sequentially arrangedand connected along a length direction of the coring instrument. Thedetection portion 501 is rotatably installed on the base body 400 andone end thereof is extended into the core channel 401, so that the corepassing through the core channel 401 can push the detection portion torotate. Meanwhile, the connecting rod assembly 502 can be pulled by therotating detection portion 501 to trigger the travel switch 503 tooperate, thereby realizing real-time core detection. Therefore, the coreswitch mechanism of this embodiment adopts a connecting rod structure,and the kinematic pairs are mainly a sliding pair and a rotating pair.The structure is simpler and more reliable, and the adaptability to thehigh-temperature mud environment underground is stronger. Moreover,since the core switch mechanism is provided along the length directionof the coring instrument, the radial size and occupied space thereof canbe reduced.

Specifically, as shown in FIGS. 1 to 3 , the coring instrument furtherincludes a core pushing rod configured to push cores and a core barrel200 configured to store cores. An open end of the core barrel 200 isfixed on the base body 400 and is in communication with the core channel401. The core pushing rod further includes a core pushing piston rod 801and a core pushing head 802 which are connected with each other. Thecore pushing rod is coaxially provided with the core barrel 200 and canpush the cores in the coring bit 900 into the core barrel 200 throughthe core channel 401.

As shown in FIG. 2 and FIG. 3 , the core switch mechanism 500 furtherincludes a first housing 507. The travel switch 503 is provided in thefirst housing 507. One end of the connecting rod assembly 502 needs toextend into the first housing 507, and the other end of the connectingrod assembly is connected with the detection portion 501, so that theconnecting rod assembly 502 can slide along a length direction of thefirst housing 507. Further, the first housing 507 is spaced apart fromthe base body 400 and connected with the base body 400 by two firstguide posts 522, which forms a stable fixation between the first housing507 and the base body 400. Both the first housing 507 and the firstguide posts 522 are arranged along the length direction of the coringinstrument. The first housing 507 includes a first end cap 514, a firstshell 515 and a lower joint 516 which are connected. Both ends in thelength direction of the first shell 515 are open. The first end cap 514and the lower joint 516 respectively block the two openings of the firstshell 515 to form a closed space. The first guide posts 522 are fixed tothe first end cap 514, and a cable of the travel switch 503 may be ledout via the lower joint 516. The travel switch 503 of this embodimentmay be a contact switch, a probe is provided thereon and faces theconnecting rod assembly 502. Alternatively, the travel switch may be aproximity switch or the like. In order to ensure the sealing of thefirst housing 507, a first seal is provided at a junction between thefirst end cap 514 and the first shell 515, the first seal includes afirst sealing loop 512 and a first retaining ring 513. The firstretaining ring 513 may cooperate with a stepped surface of an inner wallof the first shell 515 to limit the first sealing loop 512. The pull rod505 penetrates through the first sealing loop 512 and the firstretaining ring 513. A first sealing ring 520 is provided between thefirst sealing loop 512 and the first shell 515, and a second sealingring 521 is provided at a junction between the lower joint 516 and thefirst shell 515.

As shown in FIG. 2 , the base body 400 is provided with an installationcavity 404, the installation cavity 404 is in communication with thecore channel 401. The sector-shaped detection portion 501 is installedin the installation cavity 404 through a first rotating shaft 517. In aninitial state, one end of the detection portion 501 extends into thecore channel 401, which may interfere with the travel of the corepassing through the core channel 401, thus the core passing through thecore channel 401 may push the detection portion 501 to rotatecounterclockwise. The other end of the detection portion 501 is hingedwith the connecting rod assembly 502 through a fourth rotating shaft518, so that the counterclockwise rotating detection portion 501 maypull the connecting rod assembly 502 away from the travel switch 503.

For the connecting rod assembly 502, as shown in FIG. 2 and FIG. 3 , theconnecting rod assembly 502 includes a connecting rod 523 and a pull rod505. Two ends of the connecting rod 523 are respectively hinged with thedetection portion 501 and the pull rod 505 through the fourth rotatingshaft 518 and a fifth rotating shaft 519. The pull rod 505 extends inthe length direction of the coring instrument (i.e., parallel to theaxial direction of the core barrel 200) and one end thereof is extendedinto the first housing 507. The base body 400 is provided with acommunication channel 406 in communication with the installation cavity404, so that the connecting rod 523 connected with the detection portion501 may extend out of the installation cavity 404. The one end of thepull rod 505 extending into the first housing 507 is connected with aguide base 508, and the size of the guide base 508 is matched with theinternal profile of the first shell 515, so that the pull rod 505 mayslide along the length direction of the first housing 507. In order toenable the connecting rod assembly 502 to trigger the travel switch 503,the guide base 508 is provided with an insulating sleeve 509 on a sidefacing the travel switch 503, and a copper screw 510 is provided on theinsulating sleeve 509. When the core switch mechanism 500 is in theinitial state, the copper screw 510 contacts the probe on the travelswitch 503 to operate the travel switch 503.

An elastic member 504 is provided at one end of the connecting rodassembly 502 connected with the travel switch 503. After the core passesthrough the core channel 401, the elastic member 504 may apply a forceto the pulled connecting rod assembly 502 to reset it. The elasticmember 504 is a spring. As shown in FIG. 2 , the spring is sleeved onthe pull rod 505 and located between the first seal and the guide base508. When the detection portion 501 pulls the connecting rod assembly502 away from the travel switch 503, the guide base 508 will press theelastic member 504. When the core pushing is absent, the elastic member504 may push the guide base 508 to move towards the travel switch 503,thus resetting the connecting rod assembly 502. In order to limit thetravel position of the guide base 508 close to the travel switch 503, apressing sleeve 511 is provided in the first housing 507. The travelswitch 503 is positioned on the lower joint 516, and the pressing sleeve511 abuts against an end face of the lower joint 516. The inner wall ofthe first shell 515 is formed with another stepped surface to preventthe pressing sleeve 511 from further moving away from the lower joint516. In the initial state, the insulating sleeve 509 is pressed againstthe pressing sleeve 511 to prevent the pull rod 505 from further movingtowards the travel switch 503.

In addition, as shown in FIG. 2 and FIG. 3 , the pull rod 505 isconnected with the connecting rod 523 through a connector 506. Theconnector 506 is fixed at one end of the pull rod 505 and locatedoutside the first housing 507, and the connector 506 is hinged with theconnecting rod 523 through the fifth rotating shaft 519. In addition,the connector 506 is further respectively sleeved on the first guideposts 522, forming a sliding connection between the connector 506 andthe first guide posts 522, and further guiding the pull rod 505, so thatthe core switch mechanism 500 forms a slider-connecting rod structure,which can further improve the operation reliability of the core switchmechanism 500.

Further as shown in FIG. 1 and FIG. 2 , the core detection devicefurther includes a displacement detector 700 and a controller 1000. Thedisplacement detector 700 is provided on the core pushing rod and maydetect a moving distance of the core pushing rod, and the controller1000 is electrically connected with the displacement detector 700 andthe travel switch 503 respectively. Therefore, when the core pushing rodpushes the core into the core channel 401 to contact and push thedetection portion 501, the travel switch 503 operates and transmits acore acquisition signal to the controller 1000. The controller 1000acquires data of the displacement detector 700 at this moment anddetects that the instrument has acquired a core. When the core passesthrough the detection portion 501, the elastic member 504 resets thecore switch mechanism 500, and the travel switch 503 operates again andtransmits a no-core signal to the controller 1000. The controller 1000acquires data b of the displacement detector 700 at this moment, andobtains the length of the acquired core from a difference value betweenthe data b and the data a.

As shown in FIG. 1 , the core detection device further includes a spacerinsertion mechanism 600. After every operation of pushing the core, thespacer insertion mechanism 600 pushes a spacer 302 to the core channel401, and the spacer 302 may physically distinguish cores of differenthorizons. The spacer insertion mechanism 600 and a spacer barrel 300 areboth fixed to the base body 400. The spacer barrel 300 is providedtherein with multiple spacers 302, and a compression spring 301 is alsoprovided in the spacer barrel. The compression spring 301 may press thespacers 302 to make them close to the base body 400. Further, as shownin FIG. 2 , the base body 400 is provided with a sliding cavity 405 incommunication with the core channel 401 and a spacer channel 407 incommunication with the spacer barrel 300. The spacer channel 407 extendsto the sliding cavity 405, so that the spacer 302 may be pushed to thesliding cavity 405 under the action of the compression spring 301, andfurther enters the core channel 401 along the sliding cavity 405 underthe pushing action of the spacer insertion mechanism 600.

As shown in FIG. 1 , FIG. 2 and FIG. 4 , the spacer insertion mechanism600 is fixed on the base body 400 and arranged along the lengthdirection of the coring instrument, which can further reduce the radialsize and occupied space of the instrument. The spacer insertionmechanism 600 includes a slider 601, a rotating arm 602, a secondhousing 604 and a cylinder body 603. The second housing 604 is fixed tothe base body 400. The cylinder body 603 is a hydraulic cylinder whichis provided in the second housing 604 and a piston rod thereof servingas an output end is connected with the slider 601 through the rotatingarm 602. The slider 601 slides in the sliding cavity 405, so that theslider 601 may be driven by the cylinder body 603 to push the spacer 302to the core channel 401.

As shown in FIG. 2 , the second housing 604 includes a second end cap607, a second shell 608 and a plug 609. Both ends in the lengthdirection of the second shell 608 are open. The second end cap 607 andthe plug 609 respectively block the two openings of the second shell 608to form another closed space. The cylinder body 603 is provided in thesecond shell 608 and the output end thereof extends out of the secondhousing 604 via the second end cap 607. As shown in FIG. 3 , the secondend cap 607 is fixed on the base body 400 by two brackets 615, which arespaced apart to form a space therebetween for installing the spacerbarrel. In addition, in order to receive the spacer barrel, the secondend cap 607 is further provided with a receiving notch 616. The plug 609is provided with an adjusting screw 610 for adjusting the position ofthe cylinder body 603 to ensure that the slider 601 is pushed in place.In addition, second guide posts 605 are further provided between thesecond end cap 607 and the base body 400, and two ends of each of thetwo second guide posts 605 are respectively connected with the secondend cap 607 and the base body 400. The output end of the cylinder body603 is provided with a connecting base 606. The connecting base 606 issleeved on the two second guide posts 605 to form a sliding connection,which may guide the connecting base 606. In order to ensure the sealingof the second housing 604, a second seal is provided at a junctionbetween the second end cap 607 and the second shell 608, the second sealincludes a second sealing loop 611 and a second retaining ring 612. Thesecond retaining ring 612 may cooperate with a stepped surface on theinner wall of the second shell 608 to limit the second sealing loop 611.The output end of the cylinder body 603 penetrates through the secondsealing loop 611 and the second retaining ring 612. A third sealing ring613 is provided between the cylinder body 603 and the inner wall of thesecond shell 608, and a fourth sealing ring 614 is provided at ajunction between the plug 609 and the second shell 608.

As shown in FIGS. 2 to 4 , a rotating arm 602 is rotatably installed oneach of the two brackets 615 through a sixth rotating shaft 621, and thetwo rotating arms 602 which are triangular-shaped are located at bothsides of the base body 400 and separated by the base body 400. Theconnecting base 606 is hinged with the rotating arms 602 at both endsthereof. Any one of the rotating arms 602 is correspondingly providedwith a second elongated hole 618 at a sharp corner thereof, and thesecond elongated hole 618 extends to an edge of the rotating arm 602 toform a notch. Two ends of the connecting base 606 are each provided witha third rotating shaft 617. The third rotating shaft 617 is insertedinto the respective second elongated hole 618 to form a hingedconnection between the connecting base 606 and the respective rotatingarm 602. The slider 601 spans across the base body 400, and both ends ofthe slider 601 are respectively hinged with two rotating arms 602. Anyone of the rotating arms 602 is correspondingly provided with a firstelongated hole 619 at the other sharp corner thereof. Both ends of theslider 601 are each provided with a second rotating shaft 620. Thesecond rotating shaft 620 is inserted into the respective firstelongated hole 619 to form a hinged connection between the slider 601and the respective rotating arm 602. Therefore, the spacer insertionmechanism 600 forms a slider pushing structure. When the output end ofthe cylinder body 603 drives the connecting base 606 to move along thesecond guide posts 605, it will drive the rotating arms 602 to rotate,and the rotating arms 602 will pull the slider 601 to slide in thesliding cavity 405. For example, when the cylinder body 603 pushes theconnecting base 606 away from the second housing 604, the rotation ofthe rotating arms 602 will pull the slider 601 to move toward the corechannel 401, and when the cylinder body 603 moves in reverse, the slider601 may be pulled back again.

As shown in FIG. 1 and FIG. 2 , the base body 400 includes a main body402 and a partition plate 403 which are separate. The partition plate403 is provided on a side of the main body 402 facing away from the corebarrel 200, and the sliding cavity 405 is formed between the main body402 and the partition plate 403. As shown in FIG. 5 , the main body 402is provided with two protruding and spaced guide ribs 409 on an end facefacing the partition plate 403 for guiding the slider 601. The two guideribs 409 extend to the core channel 401, and a chute 410 is formedbetween the two guide ribs 409 for sliding the spacer 302. During thesliding process, the end face of the slider 601 opposite to thepartition plate 403 abuts against the partition plate 403 and slides onthe partition plate 403. The main body 402 is further provided with aconnecting post 408 protruding from the guide rib 409, the connectingpost 408 is connected with the partition plate 403 and is able tosupport the partition plate 403, so that a space slightly larger thanthe thickness of a single spacer is formed between the partition plate403 and the bottom of the chute 410.

As shown in FIG. 5 and FIG. 6 , the cross section of the slider 601 isM-shaped, which includes a slider body 623 and guide grooves 622provided on both sides of the slider body, and the second rotating shaft620 is further provided outside each guide groove 622. The guide grooves622 are matched with the guide ribs 409, so that the guide grooves 622may be snapped on the guide ribs 409 to form a sliding connection. Theslider body 623 extends into the chute 410 and is spaced apart from thebottom of the chute 410 to form a gap 411 between the bottom of theslider body 623 and the bottom of the chute 410. The gap 411 in thisembodiment is set to 1 mm, so that the slider 601 may squeeze out sludgeby the gap 411 during sliding, thus avoiding jamming. In addition, anend face of the slider 601 facing the spacer 302 is provided with an arcsurface 624 corresponding to the spacer 302, so that the slider 601 isin surface contact with the spacer 302, which can further improve thestability of pushing.

The cylinder body 603 is also electrically connected with the controller1000 (not shown in the figures). When the spacers 302 are adequate, thespacers 302 will be pushed to the sliding cavity 405 under the action ofthe compression spring 301 and abut against the partition plate 403. Inthis case, after each operation of core pushing is completed, thecontroller 1000 will control the cylinder body 603 of the spacerinsertion mechanism 600 to activate, and the slider 601 will push thespacer 302 in place and push one of the spacers 302 to the core channel401, thereby completing the insertion of the spacer 302.

Combined with the above embodiments, the core switch mechanism of theembodiments of the disclosure adopts a slider-connecting rod structure,and the kinematic pairs are mainly a sliding pair and a rotating pair.The structure is simpler and more reliable, and the adaptability to thehigh-temperature mud environment underground is stronger. Moreover,since the core switch mechanism is provided along the length directionof the coring instrument, the radial size and occupied space thereof canbe reduced. According to the embodiments of the disclosure, the spacerinsertion mechanism is changed from the existing swing hydrauliccylinder structure to the slider pushing structure, and the kinematicpairs are mainly a sliding pair and a rotating pair, thereby completelyavoiding jamming and greatly improving the reliability.

According to a possible design, the connecting rod assembly is providedwith an elastic member at one end thereof connected with the travelswitch, so as to reset the connecting rod assembly after the core passesthrough the core channel to trigger the travel switch.

According to a possible design, the core detection device includes aspacer insertion mechanism fixed on the base body, the spacer insertionmechanism includes a slider and a cylinder body, an output end of thecylinder body is connected with the slider, and the slider is slidablyconnected with the base body to push a spacer to the core channel.

According to a possible design, the core switch mechanism furtherincludes a first housing connected with the base body, the connectingrod assembly includes a connecting rod and a pull rod, two ends of theconnecting rod are respectively hinged with the detection portion andthe pull rod, one end of the pull rod away from the connecting rodextends into the first housing, and the travel switch is provided in thefirst housing at an end far away from the pull rod.

According to a possible design, the first housing is connected with thebase body through a first guide post, the pull rod is hinged with theconnecting rod through a connector provided at one end of the pull rod,and the connector is slidably connected with the first guide post toguide the pull rod.

According to a possible design, the other end of the pull rod isprovided with a guide base which is configured to slide in the firsthousing, the elastic member is a spring provided in the first housing,and the spring is sleeved on the pull rod.

According to a possible design, an insulating sleeve is provided on aside of the guide base facing the travel switch, and a copper screwconfigured to trigger the travel switch is provided on the insulatingsleeve.

According to a possible design, the first housing includes a first endcap, a first shell and a lower joint which are sequentially connected;the first end cap is provided with the first guide post extending to thebase body, a first seal corresponding to the first end cap is sleeved ona portion of the pull rod in the first housing; and the elastic memberis provided between the first seal and the guide base.

According to a possible design, a pressing sleeve is provided in thefirst housing; the pressing sleeve is fixedly provided between the guidebase and the travel switch, and the pressing sleeve abuts against theinsulating sleeve to limit the guide base.

According to a possible design, the base body is provided with aninstallation cavity in communication with the core channel, and thedetection portion is installed in the installation cavity through afirst rotating shaft.

According to a possible design, the spacer insertion mechanism includesa rotating arm, the cylinder body is fixed to the base body, and theoutput end of the cylinder body is connected with the slider through therotating arm to drive the slider to slide.

According to a possible design, the base body includes a main body and apartition plate which are connected, and a sliding cavity for the sliderto slide therein is formed between the main body and the partitionplate. The slider abuts against the partition plate. The main body isprovided with two guide ribs for sliding and guiding the slider, a chutefor sliding the spacer is formed between the two guide ribs, the slideris slidable on the guide ribs, and a gap is provided between the sliderand the bottom of the chute.

According to a possible design, the spacer insertion mechanism includesa second housing fixed to the base body through a bracket, the rotatingarm is rotatably installed on the bracket and is respectively hingedwith the slider and the output end of the cylinder body, and thecylinder body is provided in the second housing and the output endthereof extends out of the second housing.

According to a possible design, the slider spans across the base body,two rotating arms are respectively provided at two sides of the basebody, and each rotating arm and the slider are respectively providedwith a first elongated hole and a second rotating shaft for hingedconnection.

According to a possible design, a second guide post is provided betweenthe second housing and the base body, a connecting base is provided atthe output end of the cylinder body, the connecting base is in slidingconnection with the second guide post, and the rotating arm and theconnecting base are respectively provided with a second elongated holeand a third rotating shaft for hinged connection.

According to a possible design, the second housing includes a second endcap, a second shell and a plug which are sequentially connected, theoutput end of the cylinder body extends out of the second housingthrough the second end cap, and a second seal corresponding to thesecond end cap is provided in the second shell.

According to a possible design, the cross section of the slider isM-shaped, the slider includes guide grooves corresponding to the guideribs, and an end face of the slider facing the spacer is provided withan arc surface corresponding to the spacer.

According to a possible design, the core detection device includes acore pushing rod, a displacement detector and a controller. Thecontroller is electrically connected with the displacement detector andthe travel switch respectively, the displacement detector is provided onthe core pushing rod, and the controller calculates a core lengthaccording to a displacement data of the core pushing rod obtained by thedisplacement detector during operation of the travel switch.

According to the embodiments of the disclosure, the core switchmechanism adopts a slider-connecting rod structure, and the kinematicpairs are mainly a sliding pair and a rotating pair. The structure issimpler and more reliable, and the adaptability to the high-temperaturemud environment underground is stronger. Moreover, since the core switchmechanism is provided along the length direction of the coringinstrument, the radial size and occupied space thereof can be reduced.

According to the embodiments of the disclosure, the spacer insertionmechanism is changed from the existing swing hydraulic cylinderstructure to the slider pushing structure, and the kinematic pairs aremainly a sliding pair and a rotating pair, thereby completely avoidingjamming and greatly improving the reliability.

In the description of the present disclosure, it should be noted thatthe orientation or positional relations indicated by terms such as“upper”, “lower”, “one side”, “the other side”, “one end”, “the otherend”, “side”, “opposite”, “four corners”, “periphery”, “block-shapedstructure” arc based on orientation or positional relations shown in thedrawings, which arc only for facilitating describing the presentdisclosure and simplifying the description, and do not indicate or implythat the referred structure must have a specific orientation, or beconstructed and operated in a specific orientation. Therefore, theycannot be construed as limitations on the present disclosure.

In the description of embodiments of the present disclosure, unlessotherwise explicitly specified and limited, the terms “connection”,“direct connection”, “indirect connection”, “fixed connection”,“installation” and “assembly” should be broadly understood. For example,a connection may be fixed connection, detachable connection orintegrated connection. The terms “installation”, “connection” and “fixedconnection” may refer to direct connection, or indirect connectionthrough an intermediate medium, or internal communication of twoelements. For those of ordinary skills in the art, the specific meaningsof the above terms in the present disclosure may be understood accordingto specific situations.

While the embodiments disclosed in the invention are as above, theforegoing contents merely are embodiments employed for easy tounderstanding the disclosure, and are not intended to limit thedisclosure. Without departing from the spirit and scope of thedisclosure, any person skilled in the field of the invention can makeany modifications and changes in the implementation form and details,but the protection scope of patent of the disclosure shall still besubject to the definition of the appended claims.

What is claimed is:
 1. A core detection device of a coring instrument,comprising: a base body and a core switch mechanism provided on the basebody, the base body being provided with a core channel in communicationwith a core barrel, wherein the core switch mechanism comprises adetection portion, a connecting rod assembly and a travel switch whichare sequentially arranged and connected along a length direction of thecoring instrument; the detection portion is rotatably installed on thebase body and one end thereof is extended into the core channel, so thata core passing through the core channel pushes the detection portion torotate, and the connecting rod assembly is capable of being pulled bythe rotating detection portion to trigger the travel switch to operate;wherein an elastic member is provided at one end of the connecting rodassembly connected with the travel switch and configured to reset theconnecting rod assembly after the core passes through the core channel,so as to trigger the travel switch; wherein the core switch mechanismfurther comprises a first housing connected with the base body, theconnecting rod assembly comprises a connecting rod and a pull rod, twoends of the connecting rod are respectively hinged with the detectionportion and the pull rod, one end of the pull rod away from theconnecting rod extends into the first housing, and the travel switch isprovided in the first housing at one end away from the pull rod; whereinthe first housing is connected with the base body through a first guidepost, and the pull rod is hinged with the connecting rod through aconnector provided at one end of the pull rod, and the connector isslidably connected with the first guide post for guiding the pull rod.2. The core detection device of the coring instrument according to claim1, comprising a spacer insertion mechanism fixed on the base body,wherein the spacer insertion mechanism comprises a slider and a cylinderbody, an output end of the cylinder body is connected with the slider,and the slider is slidably connected with the base body to push a spacerto the core channel.
 3. The core detection device of the coringinstrument according to claim 2, wherein the spacer insertion mechanismcomprises a rotating arm, the cylinder body is fixed to the base body,and an output end of the cylinder body is connected with the sliderthrough the rotating arm to drive the slider to slide.
 4. The coredetection device of the coring instrument according to claim 3, whereinthe base body comprises a main body and a partition plate which areconnected with each other, and a sliding cavity for the slider to slidetherein is formed between the main body and the partition plate; theslider abuts against the partition plate; the main body is provided withtwo guide ribs configured to guide the sliding of the slider, a chutefor the spacer to slide therein is formed between the two guide ribs,the slider is slidable on the guide ribs, and a gap is provided betweenthe slider and a bottom of the chute.
 5. The core detection device ofthe coring instrument according to claim 4, wherein the slider has anM-shaped cross section and comprises guide grooves corresponding to theguide ribs, and an end face of the slider facing the spacer is providedwith an arc surface corresponding to the spacer.
 6. The core detectiondevice of the coring instrument according to claim 3, wherein the spacerinsertion mechanism comprises a second housing fixed to the base bodythrough a bracket, the rotating arm is rotatably installed on thebracket and respectively hinged with the slider and the output end ofthe cylinder body, and the cylinder body is provided in the secondhousing and the output end of the cylinder body extends out of thesecond housing.
 7. The core detection device of the coring instrumentaccording to claim 6, wherein the slider spans across the base body, tworotating arms are respectively provided at two sides of the base body,and each rotating arm and the slider are respectively provided with afirst elongated hole and a second rotating shaft for a hingedconnection.
 8. The core detection device of the coring instrumentaccording to claim 7, wherein a second guide post is provided betweenthe second housing and the base body, a connecting base is provided atthe output end of the cylinder body, the connecting base is slidablyconnected with the second guide post, and each rotating arm and theconnecting base are respectively provided with a second elongated holeand a third rotating shaft for a hinged connection.
 9. The coredetection device of the coring instrument according to claim 6, whereinthe second housing comprises a second end cap, a second shell and a plugwhich are sequentially connected, the output end of the cylinder bodyextends out of the second housing through the second end cap, and asecond seal corresponding to the second end cap is provided in thesecond shell.
 10. The core detection device of the coring instrumentaccording to claim 2, wherein the core detection device comprises a corepushing rod, a displacement detector and a controller, the controller iselectrically connected with the displacement detector and the travelswitch respectively, the displacement detector is provided on the corepushing rod, and the controller is configured to calculate a core lengthaccording to a displacement data of the core pushing rod obtained by thedisplacement detector during operation of the travel switch.
 11. Thecore detection device of the coring instrument according to claim 1,wherein the other end of the pull rod is provided with a guide basewhich is configured to slide in the first housing, the elastic member isa spring provided in the first housing, and the spring is sleeved on thepull rod.
 12. The core detection device of the coring instrumentaccording to claim 11, wherein an insulating sleeve is provided on aside of the guide base facing the travel switch, and a copper screwconfigured to trigger the travel switch is provided on the insulatingsleeve.
 13. The core detection device of the coring instrument accordingto claim 12, wherein a pressing sleeve is provided in the first housing,the pressing sleeve is fixedly provided between the guide base and thetravel switch and abuts against the insulating sleeve to limit the guidebase.
 14. The core detection device of the coring instrument accordingto claim 11, wherein the first housing comprises a first end cap, afirst shell and a lower joint which are sequentially connected, thefirst end cap is provided with the first guide post extending to thebase body, a first seal corresponding to the first end cap is sleeved ona portion of the pull rod in the first housing, and the elastic memberis provided between the first seal and the guide base.
 15. The coredetection device of the coring instrument according to claim 1, whereinthe base body is provided with an installation cavity in communicationwith the core channel, and the detection portion is installed in theinstallation cavity through a first rotating shaft.
 16. The coredetection device of the coring instrument according to claim 1, whereinthe core detection device comprises a core pushing rod, a displacementdetector and a controller, the controller is electrically connected withthe displacement detector and the travel switch respectively, thedisplacement detector is provided on the core pushing rod, and thecontroller is configured to calculate a core length according to adisplacement data of the core pushing rod obtained by the displacementdetector during operation of the travel switch.